Isolation and mutation trend analysis of influenza A virus subtype H9N2 in Egypt
Isolation and mutation trend analysis of influenza A virus subtype H9N2 in Egypt
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DOI：
10.1186/1743-422x-9-173
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发表时间：
2012-08-27
期刊：
影响因子：
4.8
通讯作者：
El-Kady, Magdy F.
中科院分区：
文献类型：
--
作者：
Abdel-Moneim, Ahmed S.;Afifi, Manal A.;El-Kady, Magdy F.
背景：禽流感病毒H9N2是一种影响家禽的流行性传染病病原体，可引起轻度至中度呼吸窘迫，但具有高发病率和相当高的死亡率。H9N2从禽类向哺乳动物宿主的种间传播确实存在。该病毒具有人类病毒样受体特异性，可感染人类，产生流感样疾病。方法：最近在接种H5N1疫苗的鸡群中发现了轻微的流感样症状。从感染禽群中分离出甲型流感H9N2亚型。通过对病毒基因进行测序以筛选可能的病毒重组来研究病毒的进化。将分离的H9N2毒株的病毒氨基酸序列与流感数据库中的其他相关序列进行比较，用于评估突变趋势的稳健性。与物种相关的氨基酸残基的变化或对哺乳动物产生毒力的氨基酸残基的变化被分配。结果：血凝素和神经氨酸酶基因的系统发育分析表明，最近分离的埃及菌株属于在以色列流行的H9N2亚谱系。分离的病毒的6个内部片段被发现来自同一亚谱系，没有新的重组证据。结果表明中东地区H9N2病毒具有保守的遗传和生物学结构。最近从埃及鸡中分离出的H9N2病毒所含的氨基酸可使该病毒在哺乳动物中复制，并在家鸡中引起严重疾病。结论：该研究强调了持续监测禽流感病毒演变的突变及其对禽类毒力的影响的重要性，以及它在出现有可能成为大流行候选者的新毒株方面的重要性。
Background: Avian influenza virus H9N2 is a panzootic pathogen that affects poultry causing mild to moderate respiratory distress but has been associated with high morbidity and considerable mortality. Interspecies transmission of H9N2 from avian species to mammalian hosts does occur. The virus possesses human virus-like receptor specificity and it can infect humans producing flu-like illness.Methods: Recently, mild influenza like symptoms were detected in H5N1 vaccinated flocks. Influenza A subtype H9N2 was isolated from the infected flock. The virus evolution was investigated by sequencing the viral genes to screen the possible virus recombination. The viral amino acid sequences from the isolated H9N2 strains were compared to other related sequences from the flu data base that were used to assess the robustness of the mutation trend. Changes in the species-associated amino acid residues or those that enabled virulence to mammals were allocated.Results: Phylogenetic analyses of haemagglutinin and neuraminidase genes showed that the recently isolated Egyptian strain belonged to the H9N2 sub-lineage that prevails in Israel. The six internal segments of the isolated virus were found to be derived from the same sub-lineage with no new evidence of reassortment. The results demonstrated conserved genetic and biological constitution of H9N2 viruses in the Middle East. The recently isolated H9N2 virus from chicken in Egypt possessed amino acids that could enable the virus to replicate in mammals and caused severe disease in domestic chickens.Conclusion: The study highlights the importance of continuous monitoring of the mutations evolved in avian influenza viruses and its impact on virulence to avian species in addition to its importance in the emergence of new strains with the capacity to be a pandemic candidate.